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Subject[tip:x86/olpc] x86, olpc: Add XO-1 suspend/resume support
Commit-ID:  97c4cb71c18fe045a763ff6681a8ebbbbbec0b2b
Gitweb: http://git.kernel.org/tip/97c4cb71c18fe045a763ff6681a8ebbbbbec0b2b
Author: Daniel Drake <dsd@laptop.org>
AuthorDate: Sat, 25 Jun 2011 17:34:11 +0100
Committer: H. Peter Anvin <hpa@linux.intel.com>
CommitDate: Wed, 6 Jul 2011 14:44:32 -0700
x86, olpc: Add XO-1 suspend/resume support

Add code needed for basic suspend/resume of the XO-1 laptop.
Based on earlier work by Jordan Crouse, Andres Salomon, and others.

This patch incorporates all earlier feedback from Thomas Gleixner. To
clarify a certain point (now more obvious in the code itself):
On resume, OpenFirmware returns execution to Linux in protected mode
with a kernel-compatible GDT already set up. The changes and
simplifications suggested have all been included.

Signed-off-by: Daniel Drake <dsd@laptop.org>
Link: http://lkml.kernel.org/r/1309019658-1712-5-git-send-email-dsd@laptop.org
Acked-by: Andres Salomon <dilinger@queued.net>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
---
arch/x86/Kconfig | 4 +-
arch/x86/include/asm/olpc.h | 15 +++-
arch/x86/platform/olpc/Makefile | 2 +-
arch/x86/platform/olpc/olpc-xo1-pm.c | 92 +++++++++++++++++++++++++
arch/x86/platform/olpc/xo1-wakeup.S | 124 ++++++++++++++++++++++++++++++++++
include/linux/cs5535.h | 3 +
6 files changed, 234 insertions(+), 6 deletions(-)
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 29615ee..f473151 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -2075,10 +2075,10 @@ config OLPC

config OLPC_XO1_PM
bool "OLPC XO-1 Power Management"
- depends on OLPC && MFD_CS5535
+ depends on OLPC && MFD_CS5535 && PM_SLEEP
select MFD_CORE
---help---
- Add support for poweroff of the OLPC XO-1 laptop.
+ Add support for poweroff and suspend of the OLPC XO-1 laptop.

endif # X86_32

diff --git a/arch/x86/include/asm/olpc.h b/arch/x86/include/asm/olpc.h
index 5ca6801..10ea595 100644
--- a/arch/x86/include/asm/olpc.h
+++ b/arch/x86/include/asm/olpc.h
@@ -76,6 +76,12 @@ static inline int olpc_has_dcon(void)

#endif

+#ifdef CONFIG_OLPC_XO1_PM
+extern void do_olpc_suspend_lowlevel(void);
+extern void olpc_xo1_pm_wakeup_set(u16 value);
+extern void olpc_xo1_pm_wakeup_clear(u16 value);
+#endif
+
extern int pci_olpc_init(void);

/* EC related functions */
@@ -88,9 +94,12 @@ extern int olpc_ec_mask_unset(uint8_t bits);

/* EC commands */

-#define EC_FIRMWARE_REV 0x08
-#define EC_WLAN_ENTER_RESET 0x35
-#define EC_WLAN_LEAVE_RESET 0x25
+#define EC_FIRMWARE_REV 0x08
+#define EC_WAKE_UP_WLAN 0x24
+#define EC_WLAN_LEAVE_RESET 0x25
+#define EC_SET_SCI_INHIBIT 0x32
+#define EC_SET_SCI_INHIBIT_RELEASE 0x34
+#define EC_WLAN_ENTER_RESET 0x35

/* SCI source values */

diff --git a/arch/x86/platform/olpc/Makefile b/arch/x86/platform/olpc/Makefile
index cd25038..1ae7bed 100644
--- a/arch/x86/platform/olpc/Makefile
+++ b/arch/x86/platform/olpc/Makefile
@@ -1,2 +1,2 @@
obj-$(CONFIG_OLPC) += olpc.o olpc_ofw.o olpc_dt.o
-obj-$(CONFIG_OLPC_XO1_PM) += olpc-xo1-pm.o
+obj-$(CONFIG_OLPC_XO1_PM) += olpc-xo1-pm.o xo1-wakeup.o
diff --git a/arch/x86/platform/olpc/olpc-xo1-pm.c b/arch/x86/platform/olpc/olpc-xo1-pm.c
index a2a59d3..6f3855a 100644
--- a/arch/x86/platform/olpc/olpc-xo1-pm.c
+++ b/arch/x86/platform/olpc/olpc-xo1-pm.c
@@ -16,6 +16,7 @@
#include <linux/platform_device.h>
#include <linux/pm.h>
#include <linux/mfd/core.h>
+#include <linux/suspend.h>

#include <asm/io.h>
#include <asm/olpc.h>
@@ -25,6 +26,85 @@
static unsigned long acpi_base;
static unsigned long pms_base;

+static u16 wakeup_mask = CS5536_PM_PWRBTN;
+
+static struct {
+ unsigned long address;
+ unsigned short segment;
+} ofw_bios_entry = { 0xF0000 + PAGE_OFFSET, __KERNEL_CS };
+
+/* Set bits in the wakeup mask */
+void olpc_xo1_pm_wakeup_set(u16 value)
+{
+ wakeup_mask |= value;
+}
+EXPORT_SYMBOL_GPL(olpc_xo1_pm_wakeup_set);
+
+/* Clear bits in the wakeup mask */
+void olpc_xo1_pm_wakeup_clear(u16 value)
+{
+ wakeup_mask &= ~value;
+}
+EXPORT_SYMBOL_GPL(olpc_xo1_pm_wakeup_clear);
+
+static int xo1_power_state_enter(suspend_state_t pm_state)
+{
+ unsigned long saved_sci_mask;
+ int r;
+
+ /* Only STR is supported */
+ if (pm_state != PM_SUSPEND_MEM)
+ return -EINVAL;
+
+ r = olpc_ec_cmd(EC_SET_SCI_INHIBIT, NULL, 0, NULL, 0);
+ if (r)
+ return r;
+
+ /*
+ * Save SCI mask (this gets lost since PM1_EN is used as a mask for
+ * wakeup events, which is not necessarily the same event set)
+ */
+ saved_sci_mask = inl(acpi_base + CS5536_PM1_STS);
+ saved_sci_mask &= 0xffff0000;
+
+ /* Save CPU state */
+ do_olpc_suspend_lowlevel();
+
+ /* Resume path starts here */
+
+ /* Restore SCI mask (using dword access to CS5536_PM1_EN) */
+ outl(saved_sci_mask, acpi_base + CS5536_PM1_STS);
+
+ /* Tell the EC to stop inhibiting SCIs */
+ olpc_ec_cmd(EC_SET_SCI_INHIBIT_RELEASE, NULL, 0, NULL, 0);
+
+ /*
+ * Tell the wireless module to restart USB communication.
+ * Must be done twice.
+ */
+ olpc_ec_cmd(EC_WAKE_UP_WLAN, NULL, 0, NULL, 0);
+ olpc_ec_cmd(EC_WAKE_UP_WLAN, NULL, 0, NULL, 0);
+
+ return 0;
+}
+
+asmlinkage int xo1_do_sleep(u8 sleep_state)
+{
+ void *pgd_addr = __va(read_cr3());
+
+ /* Program wakeup mask (using dword access to CS5536_PM1_EN) */
+ outl(wakeup_mask << 16, acpi_base + CS5536_PM1_STS);
+
+ __asm__("movl %0,%%eax" : : "r" (pgd_addr));
+ __asm__("call *(%%edi); cld"
+ : : "D" (&ofw_bios_entry));
+ __asm__("movb $0x34, %al\n\t"
+ "outb %al, $0x70\n\t"
+ "movb $0x30, %al\n\t"
+ "outb %al, $0x71\n\t");
+ return 0;
+}
+
static void xo1_power_off(void)
{
printk(KERN_INFO "OLPC XO-1 power off sequence...\n");
@@ -43,6 +123,17 @@ static void xo1_power_off(void)
outl(0x00002000, acpi_base + CS5536_PM1_CNT);
}

+static int xo1_power_state_valid(suspend_state_t pm_state)
+{
+ /* suspend-to-RAM only */
+ return pm_state == PM_SUSPEND_MEM;
+}
+
+static const struct platform_suspend_ops xo1_suspend_ops = {
+ .valid = xo1_power_state_valid,
+ .enter = xo1_power_state_enter,
+};
+
static int __devinit xo1_pm_probe(struct platform_device *pdev)
{
struct resource *res;
@@ -68,6 +159,7 @@ static int __devinit xo1_pm_probe(struct platform_device *pdev)

/* If we have both addresses, we can override the poweroff hook */
if (pms_base && acpi_base) {
+ suspend_set_ops(&xo1_suspend_ops);
pm_power_off = xo1_power_off;
printk(KERN_INFO "OLPC XO-1 support registered\n");
}
diff --git a/arch/x86/platform/olpc/xo1-wakeup.S b/arch/x86/platform/olpc/xo1-wakeup.S
new file mode 100644
index 0000000..948deb2
--- /dev/null
+++ b/arch/x86/platform/olpc/xo1-wakeup.S
@@ -0,0 +1,124 @@
+.text
+#include <linux/linkage.h>
+#include <asm/segment.h>
+#include <asm/page.h>
+#include <asm/pgtable_32.h>
+
+ .macro writepost,value
+ movb $0x34, %al
+ outb %al, $0x70
+ movb $\value, %al
+ outb %al, $0x71
+ .endm
+
+wakeup_start:
+ # OFW lands us here, running in protected mode, with a
+ # kernel-compatible GDT already setup.
+
+ # Clear any dangerous flags
+ pushl $0
+ popfl
+
+ writepost 0x31
+
+ # Set up %cr3
+ movl $initial_page_table - __PAGE_OFFSET, %eax
+ movl %eax, %cr3
+
+ movl saved_cr4, %eax
+ movl %eax, %cr4
+
+ movl saved_cr0, %eax
+ movl %eax, %cr0
+
+ # Control registers were modified, pipeline resync is needed
+ jmp 1f
+1:
+
+ movw $__KERNEL_DS, %ax
+ movw %ax, %ss
+ movw %ax, %ds
+ movw %ax, %es
+ movw %ax, %fs
+ movw %ax, %gs
+
+ lgdt saved_gdt
+ lidt saved_idt
+ lldt saved_ldt
+ ljmp $(__KERNEL_CS),$1f
+1:
+ movl %cr3, %eax
+ movl %eax, %cr3
+ wbinvd
+
+ # Go back to the return point
+ jmp ret_point
+
+save_registers:
+ sgdt saved_gdt
+ sidt saved_idt
+ sldt saved_ldt
+
+ pushl %edx
+ movl %cr4, %edx
+ movl %edx, saved_cr4
+
+ movl %cr0, %edx
+ movl %edx, saved_cr0
+
+ popl %edx
+
+ movl %ebx, saved_context_ebx
+ movl %ebp, saved_context_ebp
+ movl %esi, saved_context_esi
+ movl %edi, saved_context_edi
+
+ pushfl
+ popl saved_context_eflags
+
+ ret
+
+restore_registers:
+ movl saved_context_ebp, %ebp
+ movl saved_context_ebx, %ebx
+ movl saved_context_esi, %esi
+ movl saved_context_edi, %edi
+
+ pushl saved_context_eflags
+ popfl
+
+ ret
+
+ENTRY(do_olpc_suspend_lowlevel)
+ call save_processor_state
+ call save_registers
+
+ # This is the stack context we want to remember
+ movl %esp, saved_context_esp
+
+ pushl $3
+ call xo1_do_sleep
+
+ jmp wakeup_start
+ .p2align 4,,7
+ret_point:
+ movl saved_context_esp, %esp
+
+ writepost 0x32
+
+ call restore_registers
+ call restore_processor_state
+ ret
+
+.data
+saved_gdt: .long 0,0
+saved_idt: .long 0,0
+saved_ldt: .long 0
+saved_cr4: .long 0
+saved_cr0: .long 0
+saved_context_esp: .long 0
+saved_context_edi: .long 0
+saved_context_esi: .long 0
+saved_context_ebx: .long 0
+saved_context_ebp: .long 0
+saved_context_eflags: .long 0
diff --git a/include/linux/cs5535.h b/include/linux/cs5535.h
index e46b8b0..2facf16 100644
--- a/include/linux/cs5535.h
+++ b/include/linux/cs5535.h
@@ -70,6 +70,9 @@
#define CS5536_PM1_CNT 0x08
#define CS5536_PM_GPE0_STS 0x18

+/* CS5536_PM1_EN bits */
+#define CS5536_PM_PWRBTN (1 << 8)
+
/* VSA2 magic values */
#define VSA_VRC_INDEX 0xAC1C
#define VSA_VRC_DATA 0xAC1E

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